Not sure I get your drift, DJ. You regard Kim Johnson as part of "the left" of the Labour party? She has humiliated herself, grovelled and apologised, yes, but that's only because she doesn't want to lose her position and salary, nothing to do with being "unprepared for power". What could she do anyway, there are so few of "the left" left inside Labour that even if she was "prepared" for power there's nothing she could do. As for Corbyn, he had arguably a very slim chance of turning the party around and changing course, and with the backing of half a million members he might have succeeded, but he played by the rules of the game and the others didn't.
My point above was simply about Starmer and his demeanour of looking frightened all the time, even when he's trying to look decisive and strong. He's a hollow man and it's impossible to fake fortitude and willpower, and you can tell he knows it.